1. Field of Invention
The present invention relates to an active substance having anti-anxiety activities and a method of evaluating the same. More particularly, the present invention relates to a Chinese herbal aqueous extract and a method of in vitro evaluating anti-anxiety activities of the same.
2. Description of Related Art
Animal central nervous system (CNS) has many kinds of receptor systems for receiving and responding signals that generate from body under environmental changes. Some active natural components, which can keep spirit and mind health, perhaps function on many CNS receptors including cannabinoid receptor 1 (CB1) and other receptors. However, the nervous system suffers injury under oxidative pressure and hyper-excitatory electrical potential. Therefore, reduction of oxidative pressure and hyper-excitatory electrical potential is helpful to maintain the cell activity of the neural cells and the glial cells of the nervous system.
CB1 receptors are discovered in recent years and mainly distributed in portions of the CNS. Those portions that include hippocampus, amygdala, anterior cingulated cortex and prefrontal cortex are directly associated with emotional management and behaviors. Physiological ligands of CB1 receptors are arachidonic acid (AA) derivatives, and endogenous CB1 ligands mainly include N-arachidonoylethanolamine (anadamide) and 2-arachidonoyl glycerol (2-AG). The physiological functions of CB1 ligands can reduce pain and anxiety, increase reward and help for sleepiness. The animal experiments evidence that the anxiety is induced by blocking of CB1 receptor activation or in CB1 receptor knockout mice. Such anxiety cannot be effectively improved even through the administration of anti-anxiety drugs. These evidences indicate that the CB1 receptors have a significant impact on emotional management.
Researchers such as di Tomaso E. et al. had published a report titled as “Brain cannabinoids in chocolate” See di Tomaso E. et al. Nature 382(6593):677-678 (1996). This report evidenced that some active constituents of chocolate increased the concentration of endogenous CB1 ligands of the CNS, thereby producing a transient feeling of well-being. In addition, human milk also includes high amount of endogenous CB1 ligand, 2-AG. Other studies demonstrated that 2-AG is a very important bioactive factor for maintaining orexis and increasing survival rate of newborn animals.
However, the existing chemical drugs of anti-anxiety drugs or sleeping drugs have some disadvantages, such as temporary and permanent amnesia in long-term usage due to high effect concentration and most stimulation of the inhibitory potential of such drugs. As a result, scientists shifted to find naturally anti-anxiety active substances from plants. AA derivatives are not existed in plants, whereas more than three hundred kinds of plant fatty acid N-alkylamides (FAAs) have similar structures and biosynthesis routes with endogenous CB of animals. Among these compounds, many plants selected for reducing pain and inflammation contain active constituents that can bind to CB2 receptors. CB2 receptors are mainly distributed on immune cells, and the active constituents can affect animal immune cells through the CB2 receptors. Although there are many Chinese herbal medicines for helping tranquilization and anti-anxiety, the mechanism and related receptors of these active constituents are not clear. Moreover, there is no effective, quick and economic in vitro evaluation method for fast screening natural anti-anxiety active constituents from numerous raw materials of Chinese herbal medicines.
Therefore, it is necessary to provide an effective and precise in vitro evaluating method, thereby finding natural anti-anxiety active constituents from numerous raw materials of Chinese herbal medicines.